.\" Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
.\" Copyright (C) 2000, 2001 Internet Software Consortium.
.\" 
.\" Permission to use, copy, modify, and/or distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\" 
.\" THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
.\" REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
.\" AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
.\" INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
.\" LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
.\" OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
.\" PERFORMANCE OF THIS SOFTWARE.
.\"
.\" $Id: lwres_gnba.3,v 1.28 2009-07-11 01:12:46 tbox Exp $
.\"
.hy 0
.ad l
.\"     Title: lwres_gnba
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets v1.71.1 <http://docbook.sf.net/>
.\"      Date: Jun 30, 2000
.\"    Manual: BIND9
.\"    Source: BIND9
.\"
.TH "LWRES_GNBA" "3" "Jun 30, 2000" "BIND9" "BIND9"
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.SH "NAME"
lwres_gnbarequest_render, lwres_gnbaresponse_render, lwres_gnbarequest_parse, lwres_gnbaresponse_parse, lwres_gnbaresponse_free, lwres_gnbarequest_free \- lightweight resolver getnamebyaddress message handling
.SH "SYNOPSIS"
.nf
#include <lwres/lwres.h>
.fi
.HP 40
.BI "lwres_result_t lwres_gnbarequest_render(lwres_context_t\ *" "ctx" ", lwres_gnbarequest_t\ *" "req" ", lwres_lwpacket_t\ *" "pkt" ", lwres_buffer_t\ *" "b" ");"
.HP 41
.BI "lwres_result_t lwres_gnbaresponse_render(lwres_context_t\ *" "ctx" ", lwres_gnbaresponse_t\ *" "req" ", lwres_lwpacket_t\ *" "pkt" ", lwres_buffer_t\ *" "b" ");"
.HP 39
.BI "lwres_result_t lwres_gnbarequest_parse(lwres_context_t\ *" "ctx" ", lwres_buffer_t\ *" "b" ", lwres_lwpacket_t\ *" "pkt" ", lwres_gnbarequest_t\ **" "structp" ");"
.HP 40
.BI "lwres_result_t lwres_gnbaresponse_parse(lwres_context_t\ *" "ctx" ", lwres_buffer_t\ *" "b" ", lwres_lwpacket_t\ *" "pkt" ", lwres_gnbaresponse_t\ **" "structp" ");"
.HP 29
.BI "void lwres_gnbaresponse_free(lwres_context_t\ *" "ctx" ", lwres_gnbaresponse_t\ **" "structp" ");"
.HP 28
.BI "void lwres_gnbarequest_free(lwres_context_t\ *" "ctx" ", lwres_gnbarequest_t\ **" "structp" ");"
.SH "DESCRIPTION"
.PP
These are low\-level routines for creating and parsing lightweight resolver address\-to\-name lookup request and response messages.
.PP
There are four main functions for the getnamebyaddr opcode. One render function converts a getnamebyaddr request structure \(em
\fBlwres_gnbarequest_t\fR
\(em to the lightweight resolver's canonical format. It is complemented by a parse function that converts a packet in this canonical format to a getnamebyaddr request structure. Another render function converts the getnamebyaddr response structure \(em
\fBlwres_gnbaresponse_t\fR
to the canonical format. This is complemented by a parse function which converts a packet in canonical format to a getnamebyaddr response structure.
.PP
These structures are defined in
\fIlwres/lwres.h\fR. They are shown below.
.PP
.RS 4
.nf
#define LWRES_OPCODE_GETNAMEBYADDR      0x00010002U
.fi
.RE
.sp
.PP
.RS 4
.nf
typedef struct {
        lwres_uint32_t  flags;
        lwres_addr_t    addr;
} lwres_gnbarequest_t;
.fi
.RE
.sp
.PP
.RS 4
.nf
typedef struct {
        lwres_uint32_t  flags;
        lwres_uint16_t  naliases;
        char           *realname;
        char          **aliases;
        lwres_uint16_t  realnamelen;
        lwres_uint16_t *aliaslen;
        void           *base;
        size_t          baselen;
} lwres_gnbaresponse_t;
.fi
.RE
.sp
.PP
\fBlwres_gnbarequest_render()\fR
uses resolver context
\fIctx\fR
to convert getnamebyaddr request structure
\fIreq\fR
to canonical format. The packet header structure
\fIpkt\fR
is initialised and transferred to buffer
\fIb\fR. The contents of
\fI*req\fR
are then appended to the buffer in canonical format.
\fBlwres_gnbaresponse_render()\fR
performs the same task, except it converts a getnamebyaddr response structure
\fBlwres_gnbaresponse_t\fR
to the lightweight resolver's canonical format.
.PP
\fBlwres_gnbarequest_parse()\fR
uses context
\fIctx\fR
to convert the contents of packet
\fIpkt\fR
to a
\fBlwres_gnbarequest_t\fR
structure. Buffer
\fIb\fR
provides space to be used for storing this structure. When the function succeeds, the resulting
\fBlwres_gnbarequest_t\fR
is made available through
\fI*structp\fR.
\fBlwres_gnbaresponse_parse()\fR
offers the same semantics as
\fBlwres_gnbarequest_parse()\fR
except it yields a
\fBlwres_gnbaresponse_t\fR
structure.
.PP
\fBlwres_gnbaresponse_free()\fR
and
\fBlwres_gnbarequest_free()\fR
release the memory in resolver context
\fIctx\fR
that was allocated to the
\fBlwres_gnbaresponse_t\fR
or
\fBlwres_gnbarequest_t\fR
structures referenced via
\fIstructp\fR. Any memory associated with ancillary buffers and strings for those structures is also discarded.
.SH "RETURN VALUES"
.PP
The getnamebyaddr opcode functions
\fBlwres_gnbarequest_render()\fR,
\fBlwres_gnbaresponse_render()\fR
\fBlwres_gnbarequest_parse()\fR
and
\fBlwres_gnbaresponse_parse()\fR
all return
\fBLWRES_R_SUCCESS\fR
on success. They return
\fBLWRES_R_NOMEMORY\fR
if memory allocation fails.
\fBLWRES_R_UNEXPECTEDEND\fR
is returned if the available space in the buffer
\fIb\fR
is too small to accommodate the packet header or the
\fBlwres_gnbarequest_t\fR
and
\fBlwres_gnbaresponse_t\fR
structures.
\fBlwres_gnbarequest_parse()\fR
and
\fBlwres_gnbaresponse_parse()\fR
will return
\fBLWRES_R_UNEXPECTEDEND\fR
if the buffer is not empty after decoding the received packet. These functions will return
\fBLWRES_R_FAILURE\fR
if
pktflags
in the packet header structure
\fBlwres_lwpacket_t\fR
indicate that the packet is not a response to an earlier query.
.SH "SEE ALSO"
.PP
\fBlwres_packet\fR(3).
.SH "COPYRIGHT"
Copyright \(co 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
.br
Copyright \(co 2000, 2001 Internet Software Consortium.
.br
